Catheters to be inserted inside a body lumen such as a blood vessel, a vascular channel and the like are typically so-called “rapid-exchange type” catheters in which it is possible to relatively rapidly carry out the pulling-in and the pulling-out of a guide wire because there is provided, on the distal side of the catheter main body including a working lumen, a guide wire insertion portion having a tubular shape into which the guide wire is insertable. European Application Publication No. 0 925 801 describes an example of a rapid-exchange type balloon catheter. This balloon catheter is provided with a coil in the inside on the distal side of an inflation lumen (working lumen), and an anti-kink property in the vicinity of an opening portion of a guide wire insertion portion is improved by providing an extension portion which extends from the coil to the distal side away from the opening portion on the proximal side of the guide wire insertion portion.
However, the catheter described in European Application Publication No. 0 925 801 is configured such that the coil is exposed inside the working lumen. If this coil is used with a catheter in which a sensor is passed through the working lumen such as a catheter for diagnosis or the like which utilizes ultra-sound image diagnosis technology or optical coherence tomographic image diagnosis technology, there exists a possibility that when the catheter is bent, a portion of the sensor or the like interferes with the coil and is bit into between element wires or windings constituting the coil.